Would the development team be interested in creating a mirror on GitHub? I think it would help attract more contributors, both because of visibility and because there are lots of devs familiar with the git & github's workflow. I also have a personal interest in this: I am a heavy git user, and navigating hg commands is proving to be a bit of a headache.

The steps to create such a mirror are here: http://hgtip.com/tips/advanced/2009-11-09-create-a-git-mirror/. Doesn't seem too complicated. I would be happy to run the hg->git conversions on my laptop, and perhaps set up some scripts to automate the mirror update process.